A recent paper in Nature Climate Change challenges the widely held belief that by simply substituting fossil fuels with “alternative fuels” may not be enough to decarbonise our economies. Indeed, if I read it correctly some very tough choices lay ahead of us.
Richard York of the University of Oregon notes that due to the complex nature of economic systems, patterns of consumption and human behaviour simply this may note is the case.
The paper, “Do alternative energy sources displace fossil fuels?” (DOI: 10.1038/NCLIMATE1451)
A fundamental, generally implicit, assumption of the Intergovernmental Panel on Climate Change reports and many energy analysts is that each unit of energy supplied by non-fossil-fuel sources takes the place of a unit of energy supplied by fossil fuel sources. However, owing to the complexity of economic systems and human behaviour, it is often the case that changes aimed at reducing one type of resource consumption, either through improvements in efficiency of use or by developing substitutes do not lead to the intended outcome when net effects are considered.
York tests the following assumption:
If, as is the common assumption, non-fossil-fuel energy displaces fossil-fuel energy proportionately, the coefficient for non-fossil-fuel energy should be approximately -1, meaning, controlling for demand, for each unit of non-fossil-fuel energy produced/consumed there should be one unit of fossil-fuel energy that is not produced/consumed. Partial displacement would be indicated by a coefficient between -1 and 0. A coefficient of 0 would indicate that non-fossil-fuel energy sources are simply added on top of fossil-fuel sources, without displacing them.
Using data of from ±130 countries between the periods of 1960-2009, York developed six models to test the above assumption. Each model factored in patterns of energy usage, the influence of urbanisation and manufacturing and the use of hydro and nuclear power.
His results may surprise some:
I show that the average pattern across most nations of the world over the past fifty years is one where each unit of total national energy use from non fossil-fuel sources displaced less than one-quarter of a unit of fossil-fuel energy use and, focusing specifically on electricity, each unit of electricity generated by non-fossil-fuel sources displaced less than one-tenth of a unit of fossil-fuel-generated electricity.
York notes that:
These results challenge conventional thinking in that they indicate that suppressing the use of fossil fuel will require changes other than simply technical ones such as expanding non-fossil-fuel energy production.
It’s not that that the use of alternative fuels has no effect, but the effects have been moderate:
Based on all of the results presented above, the answer to the question presented in the title of this paper—do alternative energy sources displace fossil fuels?—is yes, but only very modestly. The common assumption that the expansion of production of alternative energy will suppress fossil-fuel energy production in equal proportion is clearly wrong. The failure of non-fossil energy sources to displace fossil ones is probably in part attributable to the established energy system where there is a lock-in to using fossil fuels as the base energy source because of their long-standing prevalence and existing infrastructure and to the political and economic power of the fossil-fuel industry.
I don’t think this should promote despair, however York hints at the choice we face:
The most effective strategy for curbing carbon emissions is likely to be one that aims to not only develop non-fossil energy sources, but also to find ways to alter political and economic contexts so that fossil-fuel energy is more easily displaced and to curtail the growth in energy consumption as much as possible. A general implication of these findings is that polices aimed at addressing global climate change should not focus principally on developing technological fixes, but should also take into account human behaviour in the context of political, economic and social systems
In other words: some very hard decisions will need to be made about decarbonising our civilisation, but ultimately these are political decisions.
The paper is behind a pay wall, but I recently took out a personal subscription to Nature in order to get access to this kind of research. In doing so I was hoping to share some of the insights of scientists with a broader audience.